The characteristics of feeding of Diaphus theta (Myctophidae) in the northwestern part of the Pacific Ocean in the Summer-Autumn period

Kosenok, N. S.; Chuchukalo, V. I.; Savinykh, V. F.

doi:10.1134/s003294520608008x

Cited by 14 publications

(9 citation statements)

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“…SCI: stomach content index, ns: not significant ues. This accorded with findings of earlier myctophid diet studies at similar latitudes in the Pacific, including those of Diaphus (Kosenok et al 2006), Notoscopelus (Uchikawa et al 2002), Stenobrachius (Moku et al 2000, Balanov et al 1995, and Triphoturus (Imsand 1981). At the same time, dietary differences are more apparent in smaller individuals of our 3 studied species, suggesting stronger competition and resource partitioning prior to the period when all species are able to consume larger, agile, and most abundant prey such as euphausiids.…”

Section: Discussionsupporting

confidence: 79%

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Trophic ecology of three dominant myctophid species in the northern California Current region

Suntsov

Brodeur²

2008

Mar. Ecol. Prog. Ser.

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The feeding ecology of 3 dominant sympatric myctophid species (Tarletonbeania crenularis, Diaphus theta, and Stenobrachius leucopsarus) in the northern California Current System was investigated based on samples collected in June, August, and September of 2006. All 3 species fed predominantly on Euphausia pacifica, the most abundant euphausiid off the central Oregon coast. In contrast, the same 3 lanternfishes showed marked variation in utilization of other principal food categories, and stronger resource partitioning was evident in smaller individuals. The proportion of euphausiids in the diet of T. crenularis and S. leucopsarus gradually increased with increasing size. D. theta at intermediate sizes (31 to 60 mm) preyed heavily upon salps and hyperiid amphipods, whereas the largest specimens consumed mostly euphausiids. S. leucopsarus showed little changes in composition of principal food categories between months, while T. crenularis and D. theta consumed more hyperiid amphipods in June, euphausiids in August, and salps in September. No feeding on salps was recorded in S. leucopsarus for the entire study period. All 3 species showed variation in feeding intensity, stomach fullness, state of digestion, and number of prey species and prey items per stomach. A divergence in feeding strategies of these co-occurring lanternfishes appears to reflect their structural morphology and generally conforms to an ecological subdivision of this midwater family into 'active' and 'inactive' species. Active myctophids (T. crenularis and D. theta) consumed significantly larger amounts of protein-rich prey such as euphausiids, hyperiid amphipods, and salps, while inactive S. leucopsarus showed higher preference for slower-moving, lipid-rich Neocalanus copepods. KEY WORDS:Myctophidae · Mesopelagic · Tarletonbeania crenularis · Diaphus theta · Stenobrachius leucopsarus · Feeding ecology · Ecomorphology · California Current Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 373: [81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96] 2008 Yamamura 2005). Myctophids represent an important trophic link between phytophagous zooplankton such as copepods and euphausiids and higher trophic level organisms such as salmon, tuna, seabirds, and marine mammals (see review in Brodeur & Yamamura 2005). They dominate the fish biomass in oceanic waters of the Northeast Pacific (Pearcy 1977, Gjøsaeter & Kawaguchi 1980, Beamish et al. 1999, and their transport onto continental shelves represents an important flux of energy into these systems, as represented in food web models of the California Current (Field et al. 2006).Three lanternfish species (Tarletonbeania crenularis, Stenobrachius leucopsarus, and Diaphus theta) form the bulk of micronekton fishes found in the NCC. These 3 species were reported to account for twothirds of all fishes collected in Isaac-Kidd midwater trawl tows in the upper 200 m off Oregon, USA (Pearcy 1964(Pearcy , 1977. Due to their high biomass and widespre...

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Section: Discussionsupporting

confidence: 79%

“…Similarly, the diet of D. theta off the Kuril Islands in Russia contained only a minor proportion of salps (Kosenok et al 2006). On the other hand, salps have often been categorized as unidentified gelatinous material (Mauchline & Gordon 1983), thus obscuring their actual proportions in diets.…”

Section: Thetamentioning

confidence: 99%

Trophic ecology of three dominant myctophid species in the northern California Current region

Suntsov

Brodeur²

2008

Mar. Ecol. Prog. Ser.

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“…Amphipod aggregations in high latitudes are important food for birds (Ogi et al 1985) and seals (Dehn et al 2007). In the subarctic, Themisto pacifica is a substantial food for squids (Uchikawa et al 2004) and fishes (Kosenok et al 2006), while in the northern sector of the California Current (CC), the species has been found in stomachs of salmon (Schabetsberger et al 2003), mackerels (Brodeur et al 1987) and myctophids (Suntsov & Brodeur 2008).…”

Section: Introductionmentioning

confidence: 99%

Seasonal variation in hyperiid amphipod abundance and diversity and influence of mesoscale structures off Baja California

Lavaniegos

Hereu²

2009

Mar. Ecol. Prog. Ser.

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Hyperiid amphipods collected during 4 IMECOCAL (Spanish acronym for Mexican Investigations of the California Current) cruises in January, April, July, and October 2005 were analyzed for seasonal variation in abundance and diversity and to determine the influence of surface circulation. The number of species was high in all seasons (between 79 and 92), but abundances showed remarkable differences. The total number of amphipods was lowest in January and highest in October (geometric means were 82 and 606 ind. 1000 m -3 respectively). Multivariate analysis based on similarity indices demonstrated a tight coupling between species composition and mesoscale structures. The largest cluster joined 67 stations, with 40% of similarity being explained by 4 species (Vibilia armata, Lestrigonus schizogeneios, Eupronoe minuta, and Primno brevidens). The geographic position of these stations coincided with the main California Current (CC) flow from spring to autumn. Subgroups were defined by minor seasonal differences. In contrast, the CC flow during winter was reduced to a meander off north Baja California, and was surrounded by oligotrophic water as indicated by the presence of the hyperiids Anchylomera blossevillei and Phrosina semilunata plus 3 of the dominant species (V. armata, E. minuta, and P. brevidens). To the south of this front, other clusters with high oceanic influence were formed. In 2005, 3 eddies were detected in the area: one anticyclonic eddy in April and 2 cyclonic eddies in July. The anticyclonic eddy located in the southwest had its own faunal cluster that had high diversity but low population density. The main species in the anticyclonic eddy was Platyscelus ovoides. Only one of the cyclonic eddies had a unique faunal identity, being strongly dominated by Vibilia armata; this was located in the north between the CC flow and the coast. The other eddy was large and situated in the middle of the area, with a faunal array analogous to that in the CC flow. Correlation between hyperiid and salp species abundances suggested that the increase in salps (Salpa fusiformis, Thalia orientalis, Cyclosalpa bakeri) in spring could be relevant, as many hyperiid species showed a strong increase at this time. However, the most correlated salp was Cyclosalpa danae, which occurred only in October. Chains of C. danae aggregates were firmly attached in the samples. This would promote the aggregation and survival of amphipod hosts, particularly small species such as Lestrigonus schizogenios and L. bengalensis.

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“…Though myctophids can swim up to 8 cm s ‒1 , translating to 6.9 km d ‒1 (Kaartvedt et al, 2009), they have little reason to travel horizontally. Consider an average Diaphus theta weighing 0.4 g (Sassa et al, 2002), which must eat 1-6% of its weight in food each day (Kosenok et al, 2006; Moku et al, 2000). If, during several hours of nighttime foraging at the surface, it capures a single medium-sized krill (10-40 mg for Euphausia pacifica , Wilson et al 2009), its energy needs will be met.…”

Section: Resultsmentioning

confidence: 99%

Multi-scale responses of scattering layers to environmental variability in Monterey Bay, California

Urmy

Horne

2016

Preprint

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A 38 kHz upward-facing echosounder was deployed on the seafloor at a depth of 875 m in Monterey Bay, CA, USA (36 • 42.748' N, 122 • 11.214' W) This 18-month record of acoustic backscatter was compared to oceanographic time series from a nearby data buoy to investigate the responses of animals in sound-scattering layers to oceanic variability at seasonal and sub-seasonal time scales. Pelagic animals, as measured by acoustic backscatter, moved higher in the water column and decreased in abundance during spring upwelling, attributed to avoidance of a shoaling oxycline and advection offshore. Seasonal changes were most evident in a non-migrating scattering layer near 500 m depth that disappeared in spring and reappeared in summer, building to a seasonal maximum in fall. At sub-seasonal time scales, similar responses were observed after individual upwelling events, though they were much weaker than the seasonal relationship. Correlations of acoustic backscatter with oceanographic vari- * Corresponding author ability also differed with depth. Backscatter in the upper water column decreased immediately following upwelling, then increased approximately 20 days later. Similar correlations existed deeper in the water column, but at increasing lags, suggesting that near-surface productivity propagated down the water column at 10-15 m d −1 , consistent with sinking speeds of marine snow measured in Monterey Bay. Sub-seasonal variability in backscatter was best correlated with sea-surface height, suggesting that passive physical transport was most important at these time scales.Physical variability is a fundamental feature of the ocean's pelagic habi-2 tat, and the responses of pelagic organisms to this variability play a large role 3 in determining their distribution, abundance, and survival. As such, under-4 standing the effects of physical change and variability on ocean life has long 5 been recognized as a central challenge in oceanography and marine ecology.6Physical variability can influence organisms at the individual or population 7 level, and its effects can be direct (e.g. advection) or indirect (e.g production 8 fertilized by upwelled nutrients). 9 "Physical-biological coupling" has most often been studied in the plank-10 ton, whose abundance and distribution are closely tied to physical variability 11 (Platt and Denman, 1975). However, because ocean currents are variable 12 across a wide range of spatial and temporal scales, the division between 13 14 physical processes is thus expected to extend from zooplankton to micronek-15 ton: animals roughly 2-10 cm in length with swimming abilities in between 16 those of drifting plankton and freely swimming nekton (Brodeur and Yama-17 mura, 2005). These include krill, pelagic shrimps, small squids, and fishes 18 such as myctophids. 19 Assemblages of micronekton are important constituents of deep scatter-20 ing layers (DSLs, Dietz 1948; Barham 1956). DSLs are layers of elevated 21 animal biomass, and consequently acoustic backscattering, which are found 22 worldwide in ...

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The characteristics of feeding of Diaphus theta (Myctophidae) in the northwestern part of the Pacific Ocean in the Summer-Autumn period

Cited by 14 publications

References 9 publications

Trophic ecology of three dominant myctophid species in the northern California Current region

Trophic ecology of three dominant myctophid species in the northern California Current region

Seasonal variation in hyperiid amphipod abundance and diversity and influence of mesoscale structures off Baja California

Multi-scale responses of scattering layers to environmental variability in Monterey Bay, California

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